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/* From extension vscode.github */
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/* From extension vscode.markdown-math */
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        <h2 id="1-写一个函数getdatestring返回当前日期为如下格式">1 写一个函数getDateString()返回当前日期为如下格式</h2>
<p><a href="https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Date">参考Date对象文档</a></p>
<pre><code class="language-js"><div><span class="hljs-string">&quot;今天是星期二，现在时间是10:22:31&quot;</span>
</div></code></pre>
<h2 id="2-写一个函数triareaa-b-c输入三角形的三条边返回计算面积">2 写一个函数triArea(a, b, c)，输入三角形的三条边，返回计算面积。</h2>
<p>已知面积公式为：<span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>a</mi><mi>r</mi><mi>e</mi><mi>a</mi><mo>=</mo><mroot><mrow><mi>s</mi><mo stretchy="false">(</mo><mi>s</mi><mo>−</mo><mi>a</mi><mo stretchy="false">)</mo><mo stretchy="false">(</mo><mi>s</mi><mo>−</mo><mi>b</mi><mo stretchy="false">)</mo><mo stretchy="false">(</mo><mi>s</mi><mo>−</mo><mi>c</mi><mo stretchy="false">)</mo></mrow><mn>2</mn></mroot></mrow><annotation encoding="application/x-tex">area = \sqrt[2]{s(s-a)(s-b)(s-c)}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.4306em;"></span><span class="mord mathnormal">a</span><span class="mord mathnormal">re</span><span class="mord mathnormal">a</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1.24em;vertical-align:-0.305em;"></span><span class="mord sqrt"><span class="root"><span class="vlist-t"><span class="vlist-r"><span class="vlist" style="height:0.7002em;"><span style="top:-2.878em;"><span class="pstrut" style="height:2.5em;"></span><span class="sizing reset-size6 size1 mtight"><span class="mord mtight"><span class="mord mtight">2</span></span></span></span></span></span></span></span><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.935em;"><span class="svg-align" style="top:-3.2em;"><span class="pstrut" style="height:3.2em;"></span><span class="mord" style="padding-left:1em;"><span class="mord mathnormal">s</span><span class="mopen">(</span><span class="mord mathnormal">s</span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mbin">−</span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mord mathnormal">a</span><span class="mclose">)</span><span class="mopen">(</span><span class="mord mathnormal">s</span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mbin">−</span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mord mathnormal">b</span><span class="mclose">)</span><span class="mopen">(</span><span class="mord mathnormal">s</span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mbin">−</span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mord mathnormal">c</span><span class="mclose">)</span></span></span><span style="top:-2.895em;"><span class="pstrut" style="height:3.2em;"></span><span class="hide-tail" style="min-width:1.02em;height:1.28em;"><svg xmlns="http://www.w3.org/2000/svg" width='400em' height='1.28em' viewBox='0 0 400000 1296' preserveAspectRatio='xMinYMin slice'><path d='M263,681c0.7,0,18,39.7,52,119
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M1001 80h400000v40h-400000z'/></svg></span></span></span><span class="vlist-s">​</span></span><span class="vlist-r"><span class="vlist" style="height:0.305em;"><span></span></span></span></span></span></span></span></span> 且  <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>s</mi><mo>=</mo><mfrac><mrow><mi>a</mi><mo>+</mo><mi>b</mi><mo>+</mo><mi>c</mi></mrow><mn>2</mn></mfrac></mrow><annotation encoding="application/x-tex">s=\frac{a+b+c}{2}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.4306em;"></span><span class="mord mathnormal">s</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1.2251em;vertical-align:-0.345em;"></span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.8801em;"><span style="top:-2.655em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">2</span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.394em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mathnormal mtight">a</span><span class="mbin mtight">+</span><span class="mord mathnormal mtight">b</span><span class="mbin mtight">+</span><span class="mord mathnormal mtight">c</span></span></span></span></span><span class="vlist-s">​</span></span><span class="vlist-r"><span class="vlist" style="height:0.345em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span></span></span></span></p>
<h2 id="3-写一个效果每隔一段时间把一个字符串的最后一个字符放到最开头的位置比如hello-world---dhello-worl---ldhello-wor一直这样下去">3 写一个效果，每隔一段时间把一个字符串的最后一个字符放到最开头的位置，比如&quot;Hello world&quot; -&gt; &quot;dHello worl&quot; -&gt; &quot;ldHello wor&quot;...一直这样下去。</h2>
<p><img src="https://tva1.sinaimg.cn/large/008i3skNly1gsahzu0877g305k01oq30.gif" alt=""></p>
<pre><code class="language-html"><div><span class="hljs-tag">&lt;<span class="hljs-name">div</span> <span class="hljs-attr">id</span>=<span class="hljs-string">&#x27;c&#x27;</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">div</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">script</span>&gt;</span><span class="javascript">
<span class="hljs-keyword">let</span> c = <span class="hljs-built_in">document</span>.getElementById(<span class="hljs-string">&#x27;c&#x27;</span>)
<span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">loopWord</span>(<span class="hljs-params">word</span>) </span>{
  <span class="hljs-comment">// 提示：用setInterval</span>
}
loopWord(<span class="hljs-string">&#x27;hello world.&#x27;</span>)
</span><span class="hljs-tag">&lt;/<span class="hljs-name">script</span>&gt;</span>

## 4 写一个程序计算现在离下一个元旦的天数。

## 5 写一个带界面的程序，计算乘法或除法的结果。

```html
<span class="hljs-meta">&lt;!DOCTYPE <span class="hljs-meta-keyword">html</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">html</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">head</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">meta</span> <span class="hljs-attr">charset</span>=<span class="hljs-string">utf-8</span> /&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">title</span>&gt;</span>计算乘法/除法<span class="hljs-tag">&lt;/<span class="hljs-name">title</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">style</span> <span class="hljs-attr">type</span>=<span class="hljs-string">&quot;text/css&quot;</span>&gt;</span><span class="css">
<span class="hljs-selector-tag">body</span> {<span class="hljs-attribute">margin</span>: <span class="hljs-number">30px</span>;}
</span><span class="hljs-tag">&lt;/<span class="hljs-name">style</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">head</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">body</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">form</span>&gt;</span>
n1 : <span class="hljs-tag">&lt;<span class="hljs-name">input</span> <span class="hljs-attr">type</span>=<span class="hljs-string">&quot;text&quot;</span> <span class="hljs-attr">id</span>=<span class="hljs-string">&quot;n1&quot;</span> /&gt;</span><span class="hljs-tag">&lt;<span class="hljs-name">br</span>&gt;</span>
n2: <span class="hljs-tag">&lt;<span class="hljs-name">input</span> <span class="hljs-attr">type</span>=<span class="hljs-string">&quot;text&quot;</span> <span class="hljs-attr">id</span>=<span class="hljs-string">&quot;n2&quot;</span> /&gt;</span><span class="hljs-tag">&lt;<span class="hljs-name">br</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">input</span> <span class="hljs-attr">type</span>=<span class="hljs-string">&quot;button&quot;</span> <span class="hljs-attr">onClick</span>=<span class="hljs-string">&quot;multiplyBy()&quot;</span> <span class="hljs-attr">Value</span>=<span class="hljs-string">&quot;乘&quot;</span> /&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">input</span> <span class="hljs-attr">type</span>=<span class="hljs-string">&quot;button&quot;</span> <span class="hljs-attr">onClick</span>=<span class="hljs-string">&quot;divideBy()&quot;</span> <span class="hljs-attr">Value</span>=<span class="hljs-string">&quot;除&quot;</span> /&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">form</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">p</span>&gt;</span>结果 : <span class="hljs-tag">&lt;<span class="hljs-name">br</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">span</span> <span class="hljs-attr">id</span>=<span class="hljs-string">&quot;result&quot;</span>&gt;</span><span class="hljs-tag">&lt;/<span class="hljs-name">span</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">p</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">body</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">html</span>&gt;</span>
</div></code></pre>
<h2 id="6-摄氏度和华氏度转换已知关系为-frac摄氏度5--frac华氏度-329">6 摄氏度和华氏度转换，已知关系为 <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mfrac><mtext>摄氏度</mtext><mn>5</mn></mfrac><mo>=</mo><mfrac><mrow><mtext>华氏度</mtext><mo>−</mo><mn>32</mn></mrow><mn>9</mn></mfrac></mrow><annotation encoding="application/x-tex">\frac{摄氏度}{5} = \frac{华氏度-32}{9}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1.2173em;vertical-align:-0.345em;"></span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.8723em;"><span style="top:-2.655em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">5</span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.394em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord cjk_fallback mtight">摄氏度</span></span></span></span></span><span class="vlist-s">​</span></span><span class="vlist-r"><span class="vlist" style="height:0.345em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1.2173em;vertical-align:-0.345em;"></span><span class="mord"><span class="mopen nulldelimiter"></span><span class="mfrac"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.8723em;"><span style="top:-2.655em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord mtight">9</span></span></span></span><span style="top:-3.23em;"><span class="pstrut" style="height:3em;"></span><span class="frac-line" style="border-bottom-width:0.04em;"></span></span><span style="top:-3.394em;"><span class="pstrut" style="height:3em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mtight"><span class="mord cjk_fallback mtight">华氏度</span><span class="mbin mtight">−</span><span class="mord mtight">32</span></span></span></span></span><span class="vlist-s">​</span></span><span class="vlist-r"><span class="vlist" style="height:0.345em;"><span></span></span></span></span></span><span class="mclose nulldelimiter"></span></span></span></span></span></h2>
<pre><code class="language-js"><div><span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">F2C</span>(<span class="hljs-params"></span>) </span>{}
<span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">C2F</span>(<span class="hljs-params"></span>) </span>{}
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